Copper ruby glass



Patented Mar. 16, 1954 OFFICE Nomrawinga ADDli -Ia'tiOmMaYTlZ,1950,Serial- N0. 161,372.87

2 ClaimSmi-(Cl. 106 52) Our lnvaentinnzrelatesstczthe art. :ofmakingscopaw per ruby glass. Copper rubyeglasses.have beenr:madeefior-imanmyearszpast, usingz'eb atch 1f ormulas including charcoal;orscream of tartar: as a Are-.

ducing agent: 1 With such reducing-agents; dif-a ficulties:are-"encountered; particularly-,ain: con-r. trollingirandzmaintainingQuniformity of: color;

More recently this wdiificulty hassbeenzlargelyovera comeibyrthei'useaof.a cyanogen compound; such;

for:zexample;i.as sodiumvcyanidegfor. a reducingaqo agentzlxTheausenotzrnetallic:cyanogenxcompounds f orcthiszzpurposea is v.rdisclosed thepatent ;to

Dobrovolnmet2112174554; October 3 F1939 ,COI-T: ored GlassffirfAlthohghgbyizthe use of s'uchncompoundss better .scolon: andsgreateruniformitysiot color are obtained, their use is highly objection=:-.-able owing rtozz'the'tifact' that'itheyc areindeadly poisonous andextrememrecautions;must'hetakem,, in glass factories where suchmaterials archandle'dsiii-Th'ezhistory of:.their.industrial use recordsmanmfatalitiessfrom :ordina-ry handling of. cyanidetmaterials;We'have'aidiscovered cthat:coaLi ground; to' a suitableifineness andinirsuitablet,quantitieszas:

geousl-yr'as a reducing: agent: in: the manufacture ofwopperz ruby:g1a'ss.::':The::ground -coal [is sure, perior to materialscisuchascharcoarandiscream of tartarw Moreover; :it': isnwelh adapted forisusein open- 'ifui'nacesyzwhereas"charcoalaands;cream-1:

of-it'artar are onlyiadaptedior use inccloseds pots: 1;; on" furnacesOur inventio'n oomprisessthe usesofisbismuthuin; smaltiamounts iincombination withuthe coal ;to:.:;

maintain and "control uniformity. of .color :of the,

which we have developed and usedin the manu-J fahture'l-iofglassware: i.

In the aboverforniulaf thevweighti-of the gredients'formingtrthe'fi-batch is given in pounds r except the last*itemrBi'smuth Subnitrate;'-given in ounces. Thesecond and thi rd columns giye a quantitative'fanalysis of the? glass producedfiy'i saidbatch? E" The' FeiOranwTiOz appear" as--im'----' purities-'in-the-glass:This glasswas processed through forming @nd hairdling equipment in* usecommerciaily =intheimanufacture of 'glass con tainrs ibottlesamr'jars)-'I'hebl'ownglass aran ticles" werer'conveyed' 'to anv annealing lehrrwhere 2 the'zco-lo'r was*fiashed 'at temperatures varying froni 980"'to1060*"degre'es The articles -'-Were the'nsubjectedto-normal"armealingtemperaturest;e The-jresultanti'--color Was=*a' clear-ruby; uniformthroughout thearticles?* Tnequantity of coal-requiredi-in a batch tormula s'uclras above given, depends upon the composition and grain sizeof the specific coal' 1 used? A -:bitu'mi-nous' coal' havinga thighfixed carbon content 'andaminimum of 'fineparticlesw (passing through140 -meshscreem we -have found 7 to be mostv-desirablew The -fine'partioles in the coal dust off'wr burn zawaybefore any-r appreciable"reaction canoccur with' other batch material's. With regard; 'to the*use ina glass batch of carbon in finely divided form, it' -is' td ziberobserved that manyprior art ruby'gla's's' -batch formulas cal'l' forcharcoalon cream-mi tartar-w- Tli'e'se formulas'apply'to'the'manufacture of ruby glass in closed pots andhave been "founduns uitable--for*use* in' open-"tanks? The" above iden tifie'd patents coveringthe-use of cyanogemmm poundsand-bismuth =representthe=first practicamethod of manufacturing copper ruby-glass im continuous-=furnacesr- Thefact that" cyanogen compounds arefleadlypoisons;even-invery 'smallsiquantities :i-renders their use-definitely undesir able? We" I 'haveconducted experiments =:with batcl'il melting-'forthe purpose' ofdeterminingthe-optimum quantity of "powdered: coal,- required aswell/ astheinfluence:ofigrainsizefi Two coals-:inthe" bituminousz'class;-referreclto respeptively -asNo: 1 coal and"No'T2 jco'al, having-thefollowingiigom positions. gwereyused these 'melts'x" Formula Percent No.1 No. 2 Sand 2000 SiOa 71.92 coal coal Soda Ash 796.8 A120; 1.78 CalciteLimestone"... 508 F8203 O39 Feldsparm 252.8 TiOz .013 Ash 12. 30 7. 87Powdered Coal. 08.0 9.32 Total Sulphur .80 1.77 Cuprous Oxide 2 4 MgO.09 Sulphur Trioxide (SO 18 .37 Stannic Oxide NazO 16. 53 Ferric Oxide(FezOa) in coal" 74 l. 16 Bismuth Subnitrate 3. 6 to 6. 8 oz Cu .071Ferric Oxide (F8103) in ash 6. 0 14.8 SD02 .213 55 V latile Matter 29.7435.30 B1 0; 006 to .011 Fixed Carbon 58.0 56.8

3 A screen analysis of these coals showed the following proportions andgrain sizes:

We found that it required 16 pound of the No. 1 coal in the batch aboveiven to G velop a copper ruby glass comp-arable to that developed withthe same batch containing only 12% lbs. of No. 2 coal. After screeninout the fines, only 12% lbs. of the No. 1 coal was required.

The above batch, when melted in a continuous tank furnace without theaddition of bismuth oxide, resulted in a glass with too critical astriking range. Bottles made with such glass were ruby colored followinglehr treatment but were streaked and varied in color intensity. Theglass was very sensitive to chilling; for example, it was not possibleto strike color in the finish unless the lehr temperature was raisedsufficiently to render the balance of the bottle opaque.

Prior to the addition of bismuth oxide, the glass easily developedopacity and a liverish color. This sensitive condition is alsocharacteristic of a glass batch containin sodium cyanide either with orWithout the addition of bismuth oxide. Following the addition of a smallquantity of bismuth to the batch containing coal, the tendency towardopacity or livering disappeared. An increase in flashing temperatureresulted only in a further increase in the intensity of the ruby color.The temperature range for flashing a good ruby color is thusconsiderably wlder than with the use of a cyanide-bismuth batch such ascovered by the above noted patents.

Our experiments with crucible melts show that the tin oxide comprised inthe above batch (formula) could be introduced as either stannous orstannic oxide without etrime-ntal effects. Since stannous oxide isunstable, limited in supply and more expensive, the use of stannic oxideis preferred for the batch used in the continuous furnace.

Our invention is not limited to the use of any specific type of glass orany particular glass formula. A desirable ruby-colored glass can be madein a standard continuous container glass furnace using a base batch(sodalime-silica) to which is added a stannous or stannic acid, cuprousoxide, and bismuth, using coal as a reducing agent. Referring to theabove glass formula, the percentages of the batch ingredients may bevaried With a resultant variation in the percentages of the lasscomponents, a follows, namely: the S102 may Vary within practical limitsfrom 68% to 72.5%; the A1203 from 5% to 3.0%; the 02.0 from 5.5% to11.5%; the MgO from .05% to 6.0%; the NazO from 14.5% to 17.0%; the Cufrom .04% to .1%; the $1102 from .12% to 25%; the BizOs as given in theformula, namely, from .006% to .011%. The BiaOs is preferably less than.0l%.

The bismuth as introduced into the glass batch may be either in the formof a subnitrate or some other salt or compound containing bismuth. Thebismuth is only used in the very small quantities necessary to controlthe color and give stability. The less the amount of bismuth, the longerthe flashing temperature must be maintained to effect a given result. Toproduce the desired color, the temperature may be temporarily raisedsomewhat higher than the usual annealin temperature; for example, up toabout 1000 degrees F. when the ware has been piaced in the annealinglehr and then reduced to the normal usual annealing temperatures.

Although the sample coals above referred to are in the bituminous class,anthracite may be used 'or any coal of intermediate composition. Theamount of coal required for optimum results would vary but would bewithin the range of from t 12 to 24 lbs. per ton of sand or from .04 to08% by weight of the finished glass. bismuth oxide required would beunder 0.01%,

averaging from 0.036 to 6.008% of the finished glass. The amount of tinand copper oxide required may be varied within limits as heretoforepointed out in connection with the formula.

Amounts and percentages herein given are by Y weight.

Modifications may be restored to within th spirit and scope of ourinvention.

We claim:

1. The method of preparing a ruby glass which comprises adding areducing agent consisting of granulated coal to a glass batch whichincludes 04% to .08% by weight of the finished glass,

and fusing said batch in an open furnace.

2. The method of preparing ruby glass which comprises adding a reducingagent consisting of granulated coal to a glass batch which includes asingredients thereof copper compound and a bismuth compound containing anamount of hismoth equivalent within the range of about 0.006% to 0.01%BiaOa, the amount of granulated coal being from 34% to 118% by weight ofthe finished glass, and fusing said batch in an open furnace.

EDWARD M. LOBDELL. JOSEPH W. WRIGHT.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date The quantity of I Dobrovalny et a1. Oct. 3, 1939 Dobrovalnyetal. Feb. 25, 1941

1. THE METHOD OF PREPARING A RUBY GLASS WHICH COMPRISES ADDING AREDUCING AGENT CONSISTING OF GRANULATED COAL TO A GLASS BATCH WHICHINCLUDES AS INGREDIENTS THEREOF A COPPER COMPOUND AND A BISMUTH COMPOUNDCONTAINING A SUBSTANTIAL AMOUNT OF BISMUTH EQUIVALENT TO LESS THAN 0.01%B12O3, THE AMOUNT OF GRANULATED COAL BEING FROM .04% TO .08% BY WEIGHTOF THE FINISHED GLASS, AND FUSING SAID BATCH IN AN OPEN FURNACE.